The effects of indoor air pollutants range from short-term effects – eye and throat irritation – to long-term effects – respiratory disease and cancer. Exposure to high levels of some pollutants, such as carbon monoxide, can even result in immediate death. Also, some indoor pollutants can magnify the effects of other indoor pollutants. Based on cancer risk alone, federal scientists have ranked indoor air pollution as one of the most important environmental problems in the United States.